D.3.7 Changes in release 4.0.9 (09 Jan 2003)

Functionality added or changed:

• OPTIMIZE TABLE will for MyISAM tables treat all NULL values as different when calculating cardinality. This helps in optimising joins between tables where one of the tables has a lot of NULL values in a indexed column:

  SELECT * from t1,t2 where t1.a=t2.key_with_a_lot_of_null;
  

• Added join operator FORCE INDEX (key_list). This acts likes USE INDEX (key_list) but with the addition that a table scan is assumed to be VERY expensive. One bad thing with this is that it makes FORCE a reserved word.
• Reset internal row buffer in MyISAM after each query. This will reduce memory in the case you have a lot of big blobs in a table.

Bugs fixed:

• A security patch in 4.0.8 causes the mysqld server to die if the remote hostname can't be resolved. This is now fixed.
• Fixed crash when replication big LOAD DATA INFILE statement that caused log rotation.

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